Dog with spinal cord compression from extramedullary hematopoiesis

Abstract

CASE DESCRIPTION: An 11-year-old spayed female Siberian Husky was evaluated because of a 2-week history of progressive paraparesis. CLINICAL FINDINGS: Results of neurologic examination were consistent with a T3-L3 myelopathy. There were no abnormalities on CBC, and hypercalcemia was noted on serum biochemical analysis. Several hypoechoic splenic nodules were evident on abdominal ultrasonography, and results of fine-needle aspiration cytology were consistent with splenic extramedullary hematopoiesis (EMH). Two compressive, extradural masses in the dorsal epidural space of the thoracolumbar region of the spinal cord were seen on MRI images. TREATMENT AND OUTCOME: A dorsal laminectomy was performed to remove the extradural spinal masses. Results of histologic examination of tissue samples were consistent with EMH. Following surgery, clinical signs of paraparesis resolved, and there was no recurrence of the masses 24 months after surgery. CLINICAL RELEVANCE: Extramedullary hematopoesis should be considered as a differential diagnosis in dogs in which results of diagnostic imaging indicate a epidural mass. In human patients, spinal EMH usually occurs secondary to an underlying hematologic disease, but it can also occur spontaneously. Treatment options reported for humans include surgical decompression, radiation therapy, chemotherapy, and blood transfusion. The dog of this report responded favorably to surgical decompression and was clinically normal 2 years after surgery.